Planimeter.



L. A. SHELDON.

PLANIMETER.

APPLICATION FILED NOV.27, 1911.

t z 0 Inventor messes Lucian Q LSheSdO sou/Mum PLANBGRAPH Co..WASHINGTON, u. c

LUCIAN A. SHELDON, 0F

SCI-IENEOTADY, new roan, ass-lemon r0 GENERAL ELEO- TRIO COMPANY, Aconroanrron or new Yon-K.

PLANIMETER.

Specification of Letters Patent.

Patented ()ct. 21,1913.

Application filed November 27, 1911. Serial No. 662,576.

or some other value, according to the units in which the coordinates ofthe curve or diagram are expressed, and more particularly to planimetersfor so measuring curves or diagrams whose coordinates are notproportional to their height or length.

The object of the invention is the provision of an improved instrumentfor measuring or integrating curves or diagrams having suchnonproportional cohrdinates which facilitates the measurement, isrelatively simple in construction and gives accurate results.

In the accompanying drawing illustrating one of the embodiments of theinvention,

Figure 1 is a top view of the planimeter and.

a portion of the diagram to be measured; and Fig. 2 is a side view ofthe planimeter with a portion broken away.

The planimeter is illustrated as used in measuring or integrating theflow of steam or other fluid as recorded by a flow meter on its chart orsheet 3, but obviously it can be used for measuring other records,diagams, etc. The abscissas' of the chart are proportional to time andthe vertical lines 4: representing time are equally spaced. Theordinates of the chart are proportional to the rate of flow and thehorizontal lines 5 representing flow units are unequally spaced, thelines being closer together toward the top of the chart.

The sheet 3 is held on a base 6fby means of clamps or other suitabledevices. The base has a flat upper surface to receive the sheet and itmay be of any desired or convenient length. Secured to the base,preferably along one edge of the chart, is a bar or track 7 A carriage 8is slidably mounted on the track and guided thereon by pins 9 or othersuitable means. An arm 10 is pivoted at the point 11. to a projection 12on the carriage. The arm carries at one end a planimeter.

rotatably mounted measuring wheel 13 that engages the surface 14: of thebase. This surface is made of some material that affords a good uniformfrictional contact between it and the wheel. The measuring wheel isgraduated as shown and provided with a pointer 15 or an ordinaryvernier. A helically grooved cam or gear 16 is mounted on the measuringwheel spindle and drives a counting wheel 17 by means of the pins ofteeth 18, the counting wheel preferably moving through a distance equalto the pitch of the teeth for each revolution of the measuring wheel. Apointer 19 is employed to de terminethe extent of the movement of thewheel 17. H

Pivoted to an. arm or projection 20' on the carriage 8 is an arm 21carrying a tracing point at its outer end. A cam 22 is secured to thearm 21, the edge of the cam being in engagement with a follower'havingthe form of a pin or roll 23 mounted on the end of the arm 10. Thefollower 23 is kept in contact with the cam by a suitably arrangedspring, such, for example, as the spring 24:. A guard 25 may be providedto prevent accidental disengagement of the parts. Another arm orprojection 26 extends outwardly from the carriage adjacent the pivot 11and carries a wheel 27 at its outer end. This wheel runs over thesurface of the chart and tends to steady the movement of the planiineteras the tracing point is moved along the new line 28 and the carriagetravels on its track.

The manner of operating the improved planimeter is similar to that of astandard Starting from the zero line, the operator moves the tracingpoint over a time line until it intersects the flow line 28 theordinates of which are proportional to the instantaneous rates of flow,then along the flow line for a distance corresponding to the length oftime for which it is desired to integrate the flow, and then back to thezero line. Any other line parallel to the zero line may be used ifdesired, it only being necessary that the integration start and stop atthe same line. If the record or chart is very long, it may be measuredby dividing it into sections of about the length of the base6 and thenmeasuring one section .after another. The result is indicated by thecounting mechanism. As the tracing point is moved along the flow line,the cam 22 varies the inclination of the axis of the measuring wheel tothe tracing arm 21 and the line of movement of the carriage in such amanner as to correct or compensate for the variations in the spacing ofthe lines 5 of the record sheet or chart. The shape of the cam will varyaccording to the spacing of said lines.

In accordance with the provisions of the Patent Statutes, I havedescribed the principle of operation of my invention together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. A planimeter comprising a tracing arm, a measuring wheel, a supporton which the wheel is mounted, means connecting the support and thetracing arm so that they can move relatively to each other, and meansincluding a cam carried by the tracing arm for varying the angularrelation of the axis of the wheel and said arm.

2. A planimeter comprising a pivotally mounted tracing arm, means forsupporting the pivot of said arm and guiding it in a rectilinear path, ameasuring wheel, a support for the wheel that is pivotally connected tosaid means, and means including a cam on the tracing arm for varying theangular relation of th axis of the wheel and said arm.

3. A planimeter comprising a carriage, means for causing the carriage tofollow a definite path, a tracing arm, a meausring wheel, an arm onwhich themeasuring wheel is mounted, means connecting the arms to thecarriage so that they are angularly movable relative to each other, anda cam moved by one of said arms for controlling their angular relation.

4. A planimeter comprising a carriage, means for guiding the carriage ina rectilinear path, a tracing arm, a measuring wheel, an arm on whichthe measuring wheel is mounted with itsv axis arranged longitudinally ofthe arm, means connecting the arms to the carriage so that they areangularly movable relative to each other, and a cam on the tracing armfor varying the angular relation of the arms.

5. A planimeter comprising a carriage, means for guiding the carriage ina rectilinear path, a pivotally mounted tracing arm carried by thecarriage, a measuring wheel, means pivotally connected to the carriageon which the wheel is rotatably mounted, and a cam on the tracing armthat acts on .said means to vary the angular relation of the axis of thewheel to the tracing arm.

6. A planimeter comprising a carriage, means on which the carriage ismounted and caused to move over a definite path, a tracing arm pivotedto the carriage, a second arm pivoted to the carriage, a measuring wheelmounted on the second arm, and cam mechanism for transmitting motionbetween the two arms. 7

7. A planimeter comprising a carriage, means for guiding the carriage ina rectilinear path, a tracing arm pivoted to the carriage, a second armpivoted to the carriage, a measuring wheel mounted on the second arm,and a cam carried by the tracing arm that engages the other arm andmoves it about its pivot under certain conditions.

8. A planimeter comprising a carriage, a track on which the carriage isguided, a tracing arm pivoted to the carriage on one side of the track,an arm pivoted to the carriage on the other side of the track, ameasuring wheel mounted on the second arm, and means for transmittingmotion from one arm to the other 9. A planimeter comprising a carriage,a track on which the carriage is guided, a tracing arm pivoted to thecarriage on one side of the track, an arm pivoted to the carriage on theother side of the track, a measuring wheel mounted on the second arm, acam moved by the tracing arm that engages the other arm, and springmeans thatholds the arm and cam in engagement with each other.

10. A planimeter comprising a base, a carriage, a track on which thecarriage is guided in a rectilinear path, a tracing arm pivoted to thecarriage on one side of the track, an arm projecting from the carriageon the same side of the track, a wheel .rotatably mounted on the end ofthe second arm that is adapted to run over the base, an arm pivoted tothe carriage on the opposite side of the track, a measuring wheelmounted on the last arm, a follower mounted on the arm, a cam carried bythe tracing arm that engages the follower, and a spring for keeping thefollower in contact with the cam.

11. A planimeter comprising a carriage, means on which the carriage ismounted and caused to follow a definite path, a tracing arm pivoted tothe carriage, a counting mechanism pivotally connected to the carriage,said mechanism including a measuring wheel, and means for varying theangular relation of the axis of the wheel and the tracing arm as saidarm is moved.

12. A planimeter comprising a movable support, a tracing arm pivotallyconnected to the support, a measuring wheel, a support on which thewheel is mounted,'said support being pivotally connected to the firstsupport, and a cam that is actuated by the gular relation of the axis ofthe wheel and the arm as said arm is moved.

In Witness whereof, I have hereunto set my hand this 25th day ofNovember, 1911. LUCIAN A. SHELDON. Witnesses:

HELEN ORFORD, BENJAMIN B. HULL.

tracing arm for varying the angular relation of the Wheel support andsaid arm.

13. The combination of a supporting means, a tracing arm that ispivotally mounted on the supporting means, a counting mechanismpivotally connected to said means and including a measuring Wheel, andmeans including a cam for varying the anfive cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

Copies of this patent may be obtained for

